Commercial aircraft having a passenger cabin or courier area and a cargo compartment below the passenger cabin may provide lower deck facilities beyond standardized cargo pallets and containers. For example, lower deck galleys, lavatories and crew rest compartments are known. Trolley storage systems including a trolley lift between two decks may be found in modern large commercial aircraft.
The introduction of lower deck facilities leads to the occupation of cargo space, which is then not usable for cargo. Due to design constraints regarding feasible access locations, some fractions of available cargo space may remain completely unused after installing the lower deck facilities.
EP 0 606 920 B1 shows an aircraft fuselage, which is divided by a main deck to form an upper deck and a lower deck, which has its own floor, is interconnected with the upper deck and which comprises supply facilities and sanitary facilities to provide additional seating space on the upper deck.
EP 0 681 956 B1 shows an aircraft having a lower deck with a depressed floor section, which forms an aisle with a sufficient standing height.